Organic Light Emitting Device

ABSTRACT

Disclosed is an organic light emitting device, (OLED) comprising a substrate on which a driving transistor is formed, a bank formed on the substrate providing a boundary for a pixel region, a first electrode formed on the substrate and electrically connected with the driving transistor, the first electrode comprising a first and second cross sectional area both oriented in a direction perpendicular to a vertical direction of the substrate, the first area adjacent to the bank, the second area surrounded by the first area, an organic layer formed on the first electrode within the boundary provided by the bank, and a second electrode formed on the organic layer, wherein during operation of the OLED a first electric field between the first area of the first electrode and the second electrode is greater than a second electric field between the second area of the first electrode and the second electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 14/450,037, filed on AUG. 1, 2014, both of whichclaim priority from and the benefit under 35 U.S.C. §119(a) of KoreanPatent Application No. 10-2014-0060217, filed on MAY 20, 2014, both ofwhich are hereby incorporated by reference for all purposes as if fullyset forth herein.

BACKGROUND

1. Field of Art

The present invention relates to an organic light emitting device and amethod of fabricating the same.

2. Description of the Related Art

In the field of flat panel display, a liquid crystal display (LCD) oflow power consumption has widely been used so far. However, because aliquid crystal display device is a non-emissive device which cannot emitthe light in itself, there are many disadvantages in view thebrightness, the contrast ratio viewing angle, a large area and the like.

The liquid crystal display displays an image by controlling lighttransmittance of a liquid crystal using an electric field. The liquidcrystal display includes a liquid crystal panel in which liquid crystalcells are arranged in a matrix form and a driving circuit for drivingthereof.

An organic light emitting device emits light using anelectroluminescence phenomenon in which an organic compound placedbetween electrodes emits light when electric current flows between bothelectrodes. Further, an organic light emitting display device is adevice for displaying an image by controlling an amount of electriccurrent flowing to the organic compound so as to adjust an amount ofemitted light.

The organic light emitting display device has an advantage in that it ispossible to make it light and thin by emitting light using the thinorganic compound between the electrodes.

However when the layer consisting of a device is formed by a solubleprocess, there is a problem in that a light emitting uniformity isdegraded and light emitting efficiency is lowered.

SUMMARY

The present detailed description has been made to solve theabove-mentioned problems in the conventional art, and an aspect of thepresent disclosure is to supply an organic light emitting device whichprevents degradation of the light emitting uniformity and improves thelight emitting efficiency.

In accordance with one embodiment, a display devices comprises anorganic light emitting device (OLED) itself comprising a substrate onwhich a driving transistor is formed, a bank formed on the substrateproviding a boundary for a pixel region, a first electrode formed on thesubstrate and electrically connected with the driving transistor, thefirst electrode comprising a first and second cross sectional area bothoriented in a direction perpendicular to a vertical direction of thesubstrate, the first area adjacent to the bank, the second areasurrounded by the first area, an organic layer formed on the firstelectrode within the boundary provided by the bank, and a secondelectrode formed on the organic layer, wherein during operation of theOLED a first electric field between the first area of the firstelectrode and the second electrode is greater than a second electricfield between the second area of the first electrode and the secondelectrode.

As illustrated by this example embodiment, the various presentembodiments can prevent degradation of the light emitting uniformity andimproves light emitting efficiency in the organic light emitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a system configuration of an organic lightemitting display device to which exemplary embodiments are applied.

FIG. 2 is a planar view schematically illustrating an organic lightemitting device according to one embodiment.

FIG. 3 is a sectional view illustrating one example of an organic lightemitting device, which is taken alone a line A-A′ in FIG. 2, accordingto one embodiment.

FIG. 4 is a sectional view illustrating other example of an organiclight emitting device, which is taken alone a line A-A′ in FIG. 2,according to one embodiment.

FIG. 5 is a sectional view illustrating another example of an organiclight emitting device, which is taken alone a line A-A′ in FIG. 2,according to one embodiment.

FIG. 6 is a sectional view illustrating further another example of anorganic light emitting device, which is taken alone a line A-A′ in FIG.2, according to one embodiment.

FIGS. 7A to 7G are sectional views illustrating the method forfabricating the organic light device in FIG. 3 according to the otherembodiment.

FIGS. 8A to 8G are sectional views illustrating the method forfabricating the organic light device in FIG. 3 according to anotherembodiment.

FIGS. 9A to 9G are sectional views illustrating the method forfabricating the organic light device in FIG. 5 according to furtheranother embodiment.

FIGS. 10A to 10G are sectional views illustrating the method forfabricating the organic light device in FIG. 5 according to anotherembodiment.

FIG. 11 is a planar view schematically illustrating an organic lightemitting device according to further another embodiment.

FIG. 12 is a circuit diagram of FIG. 11.

FIG. 13 is a sectional view illustrating one example of an organic lightemitting device, which is taken alone a line B-B′ in FIG. 11, accordingto further another embodiment.

FIG. 14 is a sectional view illustrating an organic light emittingdevice according to further another embodiment.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, a few embodiments of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription, the same elements will be designated by the same referencenumerals although they are shown in different drawings. Further, in thefollowing description of the present invention, a detailed descriptionof known functions and configurations incorporated herein will beomitted when it may make the subject matter of the present inventionrather unclear.

In addition, terms, such as first, second, A, B, (a), (b) or the likemay be used herein when describing components of the present invention.Each of these terminologies is not used to define an essence, ordersequence or number of a corresponding component but used merely todistinguish the corresponding component from other component(s). Itshould be noted that if it is described in the specification that onecomponent is “connected,” “coupled” or “joined” to another component, athird component may be “connected,” “coupled,” and “joined” between thefirst and second components, although the first component may bedirectly connected, coupled or joined to the second component.

FIG. 1 is a view illustrating a system configuration of an organic lightemitting display device to which exemplary embodiments are applied.

Referring to FIG. 1, the organic light emitting display device 100 mayinclude a timing controller 110, a data driving unit 120, a gate drivingunit 130 and an organic light emitting diode display panel 140.

The timing controller 110 rearranges digital video data RGB receivedfrom the external system 14 in conformity with a resolution of theliquid crystal display panel 16 and supplies the rearranged digitalvideo data RGB to the data driving circuit 12. The timing controller 110also generates a data control signal DCS for controlling the operationtiming of the data driving circuit 120 and a gate control signal GCS forcontrolling operation timings of the gate driving circuit 130 by using aexternal timing signal such as a horizontal synchronization signalHsync, a vertical synchronization signal Vsync, an image data RGB, aclock signal DCLK from an external system. The timing controller 110 canalso convert the image data (data) from the external system into a datasignal format capable of using the data driver 120 and supply theconverted image data RGB′ to the data driver 120.

The data driver 120 may convert the video data RGB into a data signal(an analog pixel signal or a data voltage), for example a voltagecorresponding to a gray scale, in response to converted the video data(data′) and the data control signal received from the timing controller110, and supply it to data lines.

The gate driver 130 may supply a scan signal (a gate pulse, a scan pulseor a gate on signal) to a gate line in response to the gate controlsignal from the timing controller 110, and supply it to gate lines.

Each pixel on the display panel 140 is defined at each of intersectionregions in a matrix form on a first substrate, at which plural datalines D1 to Dn extending in one direction intersect with plural gatelines G1 to Gn extending in the other direction. Each pixel on thedisplay panel 140 may be at least one organic light emitting deviceincluding an anode as a first electrode, a cathode as a secondelectrode, and an organic light emitting layer.

FIG. 2 is a planar view schematically illustrating an organic lightemitting device according to one embodiment.

Referring to FIG. 2, an organic light emitting device 200 may includethe substrate 202 formed on an driving transistor 212, a bank or a pixeldefining layer 218 which is formed on the substrate 202 and defines theboundary of a pixel region, a first electrode 214 formed on thesubstrate 202 and electrically connected with the driving transistor 212wherein the quantity of a current flowing through a first area 114 aadjacent to the bank is larger than that through a second area 214 b, anorganic layer (not shown) formed on the substrate 202 corresponding tothe pixel region and a second electrode (not shown) formed on theorganic layer. An edge of the first electrode 214 is partiallyoverlapped with the bank 218.

The first area 214 a in the first electrode 214 consists of a monolayercomprising one of ITO (Indium tin oxide), FTO (Fluorine-doped TinOxide), ATO (Antimony Tin Oxide), AZO (Aluminum doped Zinc Oxide) andIZO (Indium Zinc Oxide) or a multilayer comprising two or more of theITO, the FTO, the ATO, the AZO and the IZO. In case the first area 214 aconsists of the multilayer, the first insulating layer 216 is furthercomprised of at least a step porting between the first electrode and theorganic layer.

The organic light emitting device 200 may comprise a plurality ofelectric lines. The plurality of electric lines comprise a scan lineextending in one direction, namely vertical direction in FIG. 2, andtransmitting a scan signal or a gate signal respectively, a data lineextending in the other direction, namely horizontal direction in FIG. 2and transmitting a data signal respectively, and a power line(hereafter, is referred as a “VDD line”) supplying a high voltage power.The VDD line is separated with the scan line in parallel. The scan lineis extended to a gate pad (not shown) in the vertical direction and thedata line is extended to a data pad(now shown) in the horizontaldirection in FIG. 2.

The data line 206 and the VDD line 208 may be formed with a monolayer ormultiple layers of at least one metal or alloy of Al, Pt, Pd, Ag, Mg,Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W and Cu, ALND, MoTi and the like.

The organic light emitting device 200 may include the electrodes 214 andthe organic layer at a pixel area which is defined at each ofintersection between the scan line 204 and the data line 206, and emit alight in accordance with a current supplied from the transistors 209 and212 formed on the substrate 202.

The first electrode 214 is connected to one end of the drivingtransistor 212 through a first contact hole 242, the other end of thedriving transistor 212 is connected to the VDD line 208, and the VDDline 208 is connected to a storage capacitor 210. The storage capacitor210 is connected to one end of a switching transistor 209 through athird contact hole 246 and the other end of the switching transistor 209is connected to the data line 206 through a second contact hole 244. Thescan line 204 is connected to a gate of the switching transistor 209.

In view of electrical function of the organic light emitting device 200,the switching transistor 209 is turned on by the scan signal suppliedthrough the scan line 204 so that the data signal supplied through thedata line 206 is transmitted to the gate electrode of the drivingtransistor 212. The storage capacitor 210 may store the data signalsupplied through the switching transistor 209 and maintain the turn-onstate during the predetermined time. The driving transistor 212 isdriven in response to the data signal stored to the storage capacitor210. The driving transistor 212 may control the driving current orvoltage supplied to the first electrode 214 in response to the datasignal.

If the driving transistor is driven, an emitting layer of the organiclayer may emit the light by the current supplied through the VDD line.When the driving current supplied through the driving transistor 212 istransmitted to the first electrode 214 and flows through the organiclayer to the second electrode, an electron and a hole is recombined inthe organic layer so as to emit the light.

Hereafter, the structure of the organic light emitting device 200 willbe described in reference with the section taken along a line A-A′according to various embodiments.

The organic light emitting device includes an organic layer, which inmany cases is curved in a concave shape. Often, this is due to theprocess of generating the organic light emitting device. A consequenceof this curvature is that the luminosity of the organic light emittingdevice varies due to varying thickness of the organic layer as a resultof the curvature. More specifically, the varying thickness affects theelectric field between the first and second electrodes on either side ofthe organic layer, causing the device to brighter where the organiclayer is thicker and dimmer where the organic layer is thinner.

The organic light emitting device is structured so as to counteract thisdifference in electric field. This may be accomplished in a number ofdifferent ways, depending upon the implementation. Generally, this isaccomplished by making the electric field comparatively larger near thefirst area of the first electrode, and/or by making the electric fieldcomparatively smaller near the second area of the first electrode. Thismay also be stated in terms of quantities other than electric field. Forexample, the quantity of a current flowing through a first area adjacentto the bank may be made larger than that through a second area, and/orthe quantity of a voltage at the first area may be made larger than thatat a second.

Different implementations may use different constructions of the organiclight emitting device to achieve this goal. In one embodiment, thethickness of the first area of the first electrode adjacent to a bank ishigher in a direction perpendicular to a vertical direction of thesubstrate than that of the second area of the first electrode notadjacent to the bank so that the electric field of the former area islarger than that of the latter. Here, the area adjacent to a bank in thefirst electrode consists of a monolayer or a multilayer.

In another embodiment, the first and second areas of the first electrodeare created using different materials that have different specificresistances. In another embodiment, the first and second areas of thefirst electrode are physically separated and are powered by differentdriving transistors having different current drivability.

To even out the electric field across the surface of the organic layer,insulating layers may be strategically placed at the boundaries between,or simply between, the first and second areas of the first electrode.

FIG. 3 is a sectional view illustrating one example of an organic lightemitting device, which is taken alone a line A-A′ in FIG. 2, accordingto one embodiment.

Referring to FIGS. 2 and 3, a first electrode 314 is formed on a firstsubstrate 302 on which the driving transistor 212, and there is formed abank 318 which defines the pixel region. An edge of the first electrode314 is partially overlapped with the bank 318. The first electrode 314is exposed through the open region of the bank 318 and an organic layer320 is formed on the first electrode 314. The second electrode 322 isformed in order to cover the bank 318 and the organic layer 320.

The first substrate 302 may be a plastic substrate includingpolyethylene terephthalate (PET), polyethylene naphthalate (PEN), andpolyimide as well as a glass substrate. Further, the first substrate 302may further include a buffer layer for isolating penetration of impureelement, which is formed thereon. The buffer layer may be formed of, forexample, a monolayer or multiple layers of silicon nitride or siliconoxide. Although not shown in FIG. 3, the first substrate 302 may includethe transistors 209 and 212 including a gate electrode, source/drainelectrodes, a gate insulating layer, an active layer and the like. Thedriving transistor 212 is electrically connected to the first electrode314.

The first electrode 302 may be either a anode or cathode. The firstelectrode 302 may be formed of, by a deposition or a liquid stateprocess, a transparent conductive material having a relatively largework function and playing a role of an anode electrode (positiveelectrode), for example, a metal oxide such as ITO (Indium tin oxide),FTO (Fluorine-doped Tin Oxide), ATO (Antimony Tin Oxide), AZO (Aluminumdoped Zinc Oxide) and IZO (Indium Zinc Oxide): Al or SnO2: Sb, andconductive polymer such as poly (3-methyl-thiophene), poly[3,4-(ethylene-1,2-di oxy)thiophene] (PEDT), polypyrrole, polyaniline,etc., but is not limited thereto. Further, the first electrode 302 mayformed of, by a soluble process, a carbon nanotube, graphene, a silvernanowire and the like. The first electrode 302 is formed with a metaloxide by either using a soluble process in which the nanowires isdispersed in the solvent phase of a mesh-type, or using a transparentmultilayer electrode of dielectric/metal/dielectric structure so at toproduce a transparent electrode. In the case of the top emission, areflection plate made of a metal material with excellent reflectionefficiency, for example, aluminum (Al) or silver (Ag), may be furtherformed as an auxiliary electrode on upper and lower portions of thefirst electrode 302 in order to improve the reflection efficiency.

In the first electrode 302 of the organic light emitting device 200according to one embodiment the thickness h_(a) of the first area 314 aadjacent to the bank 318 is larger than that h_(b) of the second areanot adjacent to the bank 318 (h_(a)>h_(b)). In other words, because theelectrical resistance value is inversely proportional to thecross-sectional area of the first electrode 302 through which theelectric current flows, the electrical resistance value of the firstarea 314 a is smaller than that of the second area 314 b. Therefore,when the switching transistor 209 is turned on, the quantity of thecurrent flowing to the first area 314 a may become larger than that ofthe second area 314 b.

There may exist a step porting between the first electrode 314 and theorganic layer 320. In this case, a first insulating layer may be formedat least a step porting between the first electrode and the organiclayer, but is not limited thereto.

The method for fabricating the first electrode 302 with the differentthicknesses will be described below in reference with FIGS. 7 and 8.

There may be the bank 318 defining the pixel region and in shape ofeclipse, namely oval. The opening is comprised in the bank 318 so thatthe first electrode 314 is exposed and an edge portion of the bank 318is overlapped with an edge portion of the first electrode 314.

Generally, the bank 318 has an unsmooth surface on which various wiresand transistors are arranged, and is used to prevent the organicmaterial from being deteriorated when an organic layer is formed on thesurface of the bank 318 which has unevenly formed steps.

The bank 318 may be formed of an inorganic insulation material such assilicon nitride (SiNx) and silicon oxide (SiOx), an organic insulationmaterial such as benzocyclobutene or acrylic resin, or a combinationthereof, but is not limited thereto.

The bank 318 may be formed in a forward tapered shape, which enables theorganic layer 320 and the second electrode 322 to be formed without astep because of the forward tapered shape of the bank 318. When theorganic layer 320 and the second electrode 322 is formed without a step,it can improve a step coverage.

The organic layer 320 is formed inside a boundary of the bank 318 on thefirst electrode 314. The organic layer 320 may include, not limitedthereto, a hole injection layer (HIL), a hole transfer layer (HTL), anemitting supplemental layer, an emitting layer (EML), an electrontransfer layer (ETL), an electron injection layer (EIL), and the likewhich are sequentially laminated so that a hole and an electron aresmoothly transferred to form an exciton.

The organic layer 320 according to one embodiment may be formed by asoluble process such as a inkjet printing, a roll to roll printing, ascreen printing, a spray coating, a dip spin coating, a blade coating, aroll-slit coating and the like, but not limited thereto, a chemicalvapor deposition, a physical vapor deposition and the like.

In more detail, the organic layer may comprise at least one of the holeinjection layer (HIL), the hole transfer layer (HTL), the emittingsupplemental layer, the emitting layer (EML), the electron transferlayer (ETL), the electron injection layer (EIL), and one of the holeinjection layer, the hole transport layer, the emitting supplementallayer, the emitting layer, the electron transport layer and the electroninjection layer is formed by the soluble process. Specifically the holeinjection layer (HIL), the hole transport layer (HTL) and the emittinglayer (EML) are formed by the soluble process.

However when the layer consisting of a device is formed by a solubleprocess, an upper surface of the organic layer 320 may be formed incurved surface as shown in FIG. 3. That is, a thickness of the organiclayer 320 in the first area 314 a is larger than a thickness thereof inthe second area 314 b, namely a central area of the organic layer 320.When the first electrode 314 is formed as a flat surface, the injectionof the hole from the first electrode 314 to the thick area of theorganic layer 320 is not so good that a light emitting uniformity can bedegraded and light emitting efficiency be lowered. In the firstelectrode 302 of the organic light emitting device 200 according to oneembodiment the thickness h_(a) of the first area 314 a is larger thanthat h_(b) of the second area 314 b. as a result, the electricalresistance value of the first area 314 a is smaller than that of thesecond area 314 b. Therefore, when the organic light emitting device isturned on, the quantity of the current flowing to the first area 314 amay become larger than that of the second area 314 b, therebymaintaining the light emitting uniformity.

The second electrode 322 is formed at entire surface of the substrate302 on the organic layer 320. The second electrode 322 may be either ananode or a cathode. In the case of the bottom emission, for example, thesecond electrode 337 may be formed of a metal with a monolayer ormultiple layers of an alloy in which a first metal, e.g., silver (Ag),and a second metal, e.g., magnesium (Mg), are mixed in a desiredproportion. The second electrode 322 may be formed by the solubleprocess using a solution including an organic metal ink or a nano inksuch as Ag, Al, Au, Ni and the like.

FIG. 4 is a sectional view illustrating other example of an organiclight emitting device, which is taken alone a line A-A′ in FIG. 2,according to one embodiment.

Referring to FIG. 4, the organic layer may comprise the hole injectionlayer 320 a, the hole transfer layer 320 b, the emitting supplementallayer 320 c, the emitting layer 320 d, the electron transfer layer 320e, the electron injection layer 320 f.

The organic layer may be formed by material for the soluble process. Forexample, the hole injection layer 320 a, the hole transport layer 320 band the emitting layer 320 d may be formed by material for the solubleprocess. In this specification, the material for the soluble process maymeans material used for forming one layer of the organic light emittingdevice 200 by the soluble process.

In detail, the hole injection layer 320 a is formed by the material forthe soluble process such as PEDOT:PSS(Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)),S-P3MEET(sulfonatedPoly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl)),

and the like, but is not limited thereto.

the hole transport layer 320 b is formed by the material for the solubleprocess such as TFP(Poly(2,7-(9,9-di-n-octylfluorene)-alt-(1,4-phenylene-((4-sec-butylphenyl)imino)-1,4-phenylene)),

TCTA (4,4′,4″-Tris(N-carbazolyl)-triphenylamine), TAPC(1,1-Bis(4-(N,N′-di(p-tolyl)amino)phenyl)cyclohexane),

a-NPD (N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′biphenyl-4,4′-diamine),TPD(N,N′-Bis-(3-methylphenyl)-N,N′-Bisphenyl(1,1′-biphenyl)-4,4′-diamine)and the like, but is not limited thereto.

Further the emitting layer 320 d may be formed by the material for thesoluble process such as combination of iridium-based complex compound asa dopant and a bipolar aromatic compound/polymer as a host, or one ofPPV (poly(p-phenylenevinylene)), PThs (poly(thiophene)s), Cyano-PPV, PPP(poly(p-phenylene)), poly(fluorene)s, PFO (polyfluorene), PF(polyfluorene), PVK (poly(9-vinylcarbazole) and the like, but is notlimited thereto.

The electron transfer layer 320 e may be formed by the material for thesoluble process such as TPBI(1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene),

and the like, but is not limited thereto.

FIG. 5 is a sectional view illustrating another example of an organiclight emitting device, which is taken alone a line A-A′ in FIG. 2,according to one embodiment.

Referring to FIG. 5, there is formed a bank 518 which defines the pixelregion. The first electrode 514 is formed on the substrate 502. An edgeof the first electrode 514 is partially overlapped with the bank 518.The first electrode 514 is electrically connected to the drivingtransistor. The quantity of the current flowing to the first area 514 aadjacent to the bank 518 may become larger than that of the second area514 b.

The first electrode 514 may be a multilayer including two or more of ITO(Indium tin oxide), FTO (Fluorine-doped Tin Oxide), ATO (Antimony TinOxide), AZO (Aluminum doped Zinc Oxide) and IZO (Indium Zinc Oxide): Alor SnO2: Sb, and conductive polymer such as poly (3-methyl-thiophene),poly [3,4-(ethylene-1,2-di oxy)thiophene] (PEDT), polypyrrole,polyaniline, etc. In this case, the first insulating layer 516 may beformed at a step portion between the first electrode 514 and the organiclayer 520.

The first electrode 514 is divided into the first area 514 a adjacent tothe bank 518 and the second area 514 b, namely a central area thereof.The first area 514 a may consist of two layers. The first area 514 a isdivided into a lower layer 514 a′ and an upper layer 514 a″ each ofwhich consists of at least one of ITO, FTO, ATO, AZO, IZO and the like.The lower layer 514 a′ and the upper layer 514 a″ may be either amonolayer with the same material or a dual layer with differentmaterials. The first area 514 b may have also two or more layers.

Meanwhile the first insulating layer 516 may be formed of an inorganicinsulation material such as silicon nitride (SiNx) and silicon oxide(SiOx), SiON, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, PZT, an organicinsulation material such as benzocyclobutene or acrylic resin, or acombination thereof, but is not limited thereto. The first insulatinglayer 516 may be formed at a step portion of the first area 514 a of thefirst electrode 514, thereby preventing the degradation by aconcentration of a charge, and a leakage current when the organic lightemitting device 200 is turned on.

The organic layer 520 may be formed on the first electrode 514 in orderto cover the first insulating layer 516. The second electrode 5322 maybe formed on the organic layer 520 in order to cover the bank 518 andthe organic layer 520.

FIG. 6 is a sectional view illustrating further another example of anorganic light emitting device, which is taken alone a line A-A′ in FIG.2, according to one embodiment.

Referring to FIG. 6, there is formed a bank 518 which defines the pixelregion. The first electrode 514 is formed on the substrate 602. An edgeof the first electrode 614 is partially overlapped with the bank 618.The first electrode 614 is electrically connected to the drivingtransistor. The quantity of the current flowing to the first area 614 aadjacent to the bank 618 may become larger than that of the second area614 b.

The first electrode 614 may be a multilayer. In this case, the firstinsulating layer 616 may be formed at a step portion between the mostupper layer of the first electrode 514 and the organic layer 520. Thesecond area 614 b not adjacent to the bank 618 may be a monolayer.

The hole injection layer 620 a, the hole transfer layer 620 b, theemitting supplemental layer 620 c, the emitting layer 620 d of theorganic layer 620 is formed inside a opening portion of the bank 618 onthe first electrode 614. And the electron transfer layer 620 e and theelectron injection layer 620 f may be formed in order to cover the bank618 and the emitting layer 620 d.

The organic layer 620 may be formed by the material for the solubleprocess, thereby beneficially reducing the number of the processesaccording to the large area of the display panel and the cost ofequipment.

The method for fabricating the first electrodes 314, 514 and 614 of theorganic light emitting device 200 will be described below.

FIGS. 7A to 7G are sectional views illustrating the method forfabricating the organic light device in FIG. 3 according to the otherembodiment.

Referring to FIGS. 7A to 7G, the first electrode 314 may be formed by apatterning process for patterning material 730 for a photoresist layerusing a halftone mask or a slit mask 732, an ashing process and anetching process.

Referring to FIG. 7A, material for the first electrode 314 is formed onthe substrate 302. The photoresist layer 730 is formed by coatingmaterial for the photoresist on the first electrode 314. The materialfor the first electrode 314 may be one of ITO, ATO, AZO, ZTO, IZO andthe like.

The above process is performed by the soluble process such as a spincoating, a roll to toll process, a screen printing and the like, achemical vapor deposition, a physical vapor deposition and the like, butis not limited thereto.

Referring to FIG. 7B, the halftone mask 732 includes a light shieldarea, a light semi-transmission area and a transparent area. Thematerial for the photoresist layer 730 is patterned by not only apositive photoresist material in which an area of the photoresist layertransparent to the light is deleted but also a negative photoresistmaterial.

The halftone mask is aligned to the precise aligned position and thenthere is performed the exposure process in which light is emitted fromthe light source to the halftone mask 732 and a pattern of the halftonemask 732 is transferred to the substrate. The material for thephotoresist layer 730 exposed is decomposed and patterned by performinga developing or an etching process.

Referring to FIGS. 7C and 7D, as a result of the patterning, an area ofthe material for the photoresist layer 730 corresponding to thetransparent area 732 c of the halftone mask 732 is completely deleted,an area of the material for the photoresist layer 730 corresponding tothe semitransmission area 732 b of the halftone mask 732 has the heightof h₂ and an area of the photoresist layer 730 corresponding to thelight shield area 732 a of the halftone mask 732 has the height ofh₁(h₁>h₂).

Next, the first electrode 314 not covered with the material for thephotoresist layer 730 is deleted through a wet etching or a dry etchingprocess.

Referring to FIGS. 7E and 7F, the photoresist layer 730 is deleted to apredetermined height through an ashing process with an ashing gas, thenthe material for the first electrode is exposed and there is completedthe first electrode 314 of FIG. 1 with the different thicknesses(h_(a)>h_(b)) by controlling an etching ratio of a wet etching or a dryetching and deleting some of the photoresist layer 730.

Referring to FIG. 7G, after completing the bank 318, the organic layer320 and the second electrode 322 is sequentially formed so that theorganic light emitting device of FIG. 3 is completed. The organic layermay be formed by material for the soluble process, but is not limitedthereto.

FIGS. 8A to 8G are sectional views illustrating the method forfabricating the organic light device in FIG. 3 according to anotherembodiment.

Referring to FIGS. 8A to 8G, the first electrode 314 may be formed bymethod for fabricating different from that of FIGS. 7A to 7G.

Referring to FIG. 8A, material 314′ for the first electrode which hasthe same height h_(b) of the first electrode 314 of FIG. 3 and materialfor the photoresist layer 830 is sequentially coated and then thesurface thereof is exposed through the mask 832. The photoresist layer830 corresponding to the light shield layer 832 a of the mask 832 keepsthe predetermined height and the photoresist layer 830 corresponding tothe transparent area 832 b is completely deleted. The material 314′ forthe first electrode is then formed by performing a wet/dry etchingprocess and a strip process.

Referring to FIGS. 8A to 8F, after the material 314′ the first electrodewith the predetermined height (h_(a)-h_(b)) and the photoresist layer831′ is sequentially laminated and the photoresist layer 831′ ispatterned using the mask 832, material 314″ for the first electrode isdeleted through a wet etching or a dry etching so that the patternedfirst electrode 314 is formed. Referring to FIG. 8G, the bank 318 isformed and then the organic layer 320 and the second electrode 322 aresequentially formed.

Although FIGS. 8A to 8G illustrates the case to use the first electrode314 with the non-constant thickness consisting of the same material, butvarious embodiments is not limited thereto and the first electrode 314is formed by the multilayer consisting of the different materials.

FIGS. 9A to 9G are sectional views illustrating the method forfabricating the organic light device in FIG. 5 according to furtheranother embodiment.

Referring to FIGS. 9A to 9G, the first electrode 514 may be formed bysequentially coating a lot of material 514′ and 514″ for the firstelectrodes on the substrate 502 and then the photoresist layer 930 isformed by coating material for the photoresist layer on the firstelectrode 514.

Referring to FIG. 9A, the halftone mask 932 including a light shieldarea 932 a, a light semi-transmission area 932 b and a transparent area932 c is aligned to the precise aligned position and then there isperformed the exposure process in which light is emitted from the lightsource to the halftone mask 932 and a pattern of the halftone mask 932is transferred to the substrate. The exposed photoresist layer 930 ispatterned by performing a process to develop the material for theexposed photoresist layer. As a result of the patterning, an area of thephotoresist layer 930 corresponding to the transparent area 932 c of thehalftone mask 932 is completely deleted, an area of the material for thephotoresist layer 930 corresponding to the semitransmission area 932 bof the halftone mask 932 has the original height and an area of thematerial for the photoresist layer 930 corresponding to the light shieldarea 932 a of the halftone mask 932 has the height some of which is gotrid of.

Referring to FIGS. 9A to 9E, material for the first electrode 514 notcovered with the photoresist layer 930 is deleted through a wet etchingor a dry etching process. The photoresist layer 930 is deleted to apredetermined height through an ashing process, then the first electrodeis exposed and the first electrode 514 of FIG. 5 the first area 514 a ofwhich consists of a multilayer is formed by controlling an etching ratioof a wet etching or a dry etching and deleting some of the photoresistlayer 930. Referring to FIG. 9F, the first insulating layer 516 may beformed at a step portion of the first electrode 514.

After then, the bank 318 is formed and then, the organic layer 320 andthe second electrode 322 are sequentially laminated.

Although FIGS. 9A to 9G illustrates the case to use the first electrode514 the first area 514 a of which consists of two layers 514 a′ and 514a″ including the different materials 514′ and 514″ respectively, butvarious embodiments is not limited thereto and the first electrode 314is formed by either including much more layers or consisting of the samematerials.

FIGS. 10A to 10G are sectional views illustrating the method forfabricating the organic light device in FIG. 5 according to anotherembodiment.

Referring to FIG. 10A, one material 514′ of the first electrode andmaterial for the photoresist layer 1030 is sequentially coated and thenthe surface thereof is exposed through the mask 1032. The material forthe photoresist layer 1030 corresponding to the light shield layer 1032a of the mask 1032 keeps the predetermined height and the material forthe photoresist layer 1030 corresponding to the transparent area 1032 bis completely deleted. The first electrode 514′ is then formed byperforming a wet/dry etching process and a strip process.

Referring to FIGS. 10B to 10E, after the other material 514″ of thefirst electrode and material for the photoresist layer 1031′ issequentially laminated and the photoresist layer 1014′ is patternedusing the mask, the other 514″ of the first electrode is deleted througha wet etching or a dry etching so that the patterned first electrode 514is formed. Referring to FIG. 10F, the first insulating layer 516 may beformed at a step portion of the first electrode 514. Referring to FIG.10G, the bank 518 is formed and then the organic layer 520 and thesecond electrode 522 are sequentially formed.

Hereafter, another embodiment including the first electrode with apredetermined height and a plurality of layers will be described below.

FIG. 11 is a planar view schematically illustrating an organic lightemitting device according to further another embodiment. FIG. 12 is acircuit diagram of FIG. 11.

Referring to FIGS. 11 and 12, an organic light emitting device 1100 mayinclude the substrate 1102 formed on two driving transistors 1112 a and1112 b, a bank or a pixel defining layer 1118 which is formed on thesubstrate 1102 and defines the boundary of a pixel region, a firstelectrode 1114 formed on the substrate 1102 and electrically connectedwith the two driving transistors 1112 a and 1112 b wherein the quantityof a current flowing through a first area 1114 a adjacent to the bank1118 is larger than that through a second area 1114 b, an organic layer(not shown) formed on the substrate 1102 corresponding to the pixelregion and a second electrode(not shown) formed on the organic layer. Anedge of the first electrode 1114 is partially overlapped with the bank1118.

The first electrode 1114 may include a first area electrode 1114 a and asecond area electrode 1114 b separated from the first area electrode1114 a. The second insulating layer 1116 may be further included betweenthe first area electrode 1114 a and the second area electrode 1114 b.

As shown, the first area electrode 1114 a may be in shape of a “u”(e.g.,

) and the second area electrode 1114 b may be in shape of rectangular,both in a direction parallel to the substrate (e.g., in a directionperpendicular to the first and second cross sectional areas of the firstelectrode). Therefore, the first area electrode 1114 a may be in shapeof enclosing the second area electrode 1114 b.

Meanwhile, the driving transistor 1112 may comprise a first drivingtransistor 1112 a electrically connected with the first area electrode1114 a and a second driving transistor 1112 b electrically connectedwith the second area electrode 1114 b, and a current drivability of thefirst driving transistor 1112 a is larger than that of the seconddriving transistor 1112 b.

The value of a channel width/a channel length of the first drivingtransistor may be larger than that of the second driving transistor, oran electron mobility of an active layer of the first driving transistormay be higher than that of the second transistor.

Generally the current drivability of the driving transistor isproportional to the channel width, namely the width of the active layeror the semiconductor layer, and is inversely proportional to the channellength. As shown, the organic light emitting device according to furtheranother embodiment is that the channel length of the first drivingtransistor 1112 a is larger than that of the second driving transistor1112 b so that the current drivability of the former 1112 a can belarger than that of the latter 1112 b. Therefore, when the organic lightemitting device 1110 is turned on, the quantity of the current flowingto the first area electrode 1114 a driven by the first drivingtransistor 1112 a may become larger than that of the second areaelectrode 1114 b driven by the second driving transistor 1112 b, therebymaintaining the light emitting uniformity.

Meanwhile the second insulating layer 1116 may be formed of an inorganicinsulation material such as silicon nitride (SiNx) and silicon oxide(SiOx), SiON, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, PZT, an organicinsulation material such as benzocyclobutene or acrylic resin, or acombination thereof, but is not limited thereto.

The organic light emitting device 1100 may comprise a plurality ofelectric lines. The plurality of electric lines comprise a scan lineextending in one direction, namely vertical direction in FIG. 11, andtransmitting a scan signal or a gate signal respectively, a data lineextending in the other direction, namely horizontal direction in FIG. 11and transmitting a data signal respectively, and a power line(hereafter, is referred as a “VDD line”) supplying a high voltage power.The VDD line is separated with the scan line in parallel. The scan line1104 is extended to a gate pad (not shown) in the vertical direction andthe data line 1106 is extended to a data pad (now shown) in thehorizontal direction in FIG. 11.

The data line 1106 and the VDD line 1108 may be formed with a monolayeror multiple layers of at least one metal or alloy of Al, Pt, Pd, Ag, Mg,Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W and Cu, ALND, MoTi and the like.

The organic light emitting device 1100 may include the electrodes 1114and the organic layer at a pixel area which is defined at each ofintersection between the scan line 1104 and the data line 1106, and emita light in accordance with a current supplied from the transistors 1109,1112 a and 1112 b formed on the substrate 1102.

The first area electrode 1114 a is connected to one end of the drivingtransistor 1112 a through a first contact hole 1142, the other end ofthe driving transistor 1112 a is connected to the VDD line 1108, and theVDD line 1108 is connected to a storage capacitor 1110. The second areaelectrode 1114 b is connected to one end of the driving transistor 1112b through a fourth contact hole 1148. The storage capacitor 1110 isconnected to one end of a switching transistor 1109 through a thirdcontact hole 1146 and the other end of the switching transistor 1109 isconnected to the data line 1106 through a second contact hole 1144. Thescan line 1104 is connected to a gate of the switching transistor 1109.

In view of electrical function of the organic light emitting device1100, the switching transistor 1109 is turned on by the scan signalsupplied through the scan line 1104 so that the data signal suppliedthrough the data line 1106 is transmitted to the gate electrode of thetwo driving transistors 1112 a and 1112 b. The storage capacitor 1110may store the data signal supplied through the switching transistor 1109and maintain the turn-on state during the predetermined time. The twodriving transistor 1112 a and 1112 b are driven in response to the datasignal stored to the storage capacitor 1110. The two driving transistors1112 a and 1112 b may control the driving current or voltage supplied tothe first area electrode 1114 a and the second area electrode 1114 b inresponse to the data signal.

If the two driving transistors 1112 a and 1112 b are driven, an emittinglayer of the organic layer may emit the light by the current suppliedthrough the VDD line 1108. When the driving currents supplied throughthe two driving transistors 1112 a and 1112 b are transmitted to thefirst area electrode 1114 a and the second area electrode 1114 brespectively, and flow through the organic layer to the secondelectrode, an electron and a hole is recombined in the organic layer soas to emit the light.

FIG. 13 is a sectional view illustrating one example of an organic lightemitting device, which is taken alone a line B-B′ in FIG. 11, accordingto further another embodiment.

Referring to FIG. 13, a first electrode 1314 is formed on a substrate1302 and there is formed a bank 1318 which defines the pixel region. Anedge of the first electrode 1314 is partially overlapped with the bank1318. The first electrode 1314 is exposed through the open region of thebank 1318 and an organic layer 1320 is formed on the first electrode1314. The second electrode 1322 is formed in order to cover the bank 318and the organic layer 1320.

The first electrode 1314 may be divided a first area electrode 1314 aadjacent to the bank 1318 and a second area electrode 1314 b notadjacent to the bank 1318. The second insulating layer 1116 may befurther included between the first area electrode 1314 a and the secondarea electrode 1314 b in order to prevent the degradation by aconcentration of a charge. The first area electrode 1314 a and thesecond area electrode 1314 b consists of at least one of ITO, FTO, ATO,AZO, IZO and the like. The first area electrode 1314 a and the secondarea electrode 1314 b may be either the same material or the differentmaterial.

The first area electrode 1314 a is electrically connected to the firstdriving transistor 1112 a and the second area electrode 1314 b iselectrically connected to the second driving transistor 1112 b.

Because the current drivability of the first driving transistor 1112 ais larger than that of the second driving transistor 1112 b, when theorganic light emitting device 1110 is turned on, the quantity of thecurrent flowing to the first area electrode 1114 a driven by the firstdriving transistor 1112 a may become larger than that of the second areaelectrode 1114 b driven by the second driving transistor 1112 b, therebypreventing the light emitting uniformity.

The bank 1318 is in shape of eclipse. The bank 1318 may be formed of aninorganic insulation material, an organic insulation material or acombination thereof, but is not limited thereto.

The organic layer 1320 is formed inside a boundary of the bank 1318 onthe first electrode 1314. The organic layer 1320 may include, notlimited thereto, a hole injection layer 1320 a, a hole transfer layer1320 b, an emitting supplemental layer 1320 c, an emitting layer 1320 d,an electron transfer layer 1320 e, an electron injection layer 1320 f,and the like which are sequentially laminated, but is not limitedthereto.

The hole injection layer 1320 a, the hole transfer layer 1320 b, theemitting supplemental layer 1320 c and the emitting layer 1320 d may beformed by a soluble process such as an inkjet printing, a roll to rollprinting, a screen printing, a spray coating, a dip spin coating, ablade coating, a roll-slit coating and the like, but not limitedthereto. And the electron transfer layer 1320 e and the electroninjection layer 1320 f may be formed on all surface of the substrate,but is not limited thereto. The organic layer 1320 is formed by asoluble process, an upper surface of the organic layer 1320 may beformed in curved surface. That is, a thickness of the organic layer 1320in the first area adjacent to the bank 1318 is larger than a thicknessthereof in the second area not adjacent to the bank 13181.

FIG. 14 is a sectional view illustrating an organic light emittingdevice according to further another embodiment.

Referring to FIG. 14, a first electrode 1414 and a bank 1418 are formedon a substrate 1402. The organic layer 1420 is formed on the firstelectrode 1414. The second electrode 1422 is formed in order to coverthe bank 318 and the organic layer 1420. The first electrode 1414 mayconsist of two or more areas different from each other one of which issurrounded by the other. A specific resistance of the surrounding areais different from that of the surrounded area in the first electrode. Aspecific resistance of the surrounding area such as the first area 1414a may be lower than one of the surrounded area such as the second area1414 b. Although the first electrode is divided into the first area 1414a and the second area 1414 b in the organic light emitting device ofFIG. 4, it may be divided into two or more areas.

Unlike the first electrode of the above-described embodiments with thedifferent thickness or separated with each other, the first electrode1414 is integrally formed with the same thickness. The first electrode1414 may consist of at least one of ITO, FTO, ATO, AZO, IZO and thelike, but it is not limited thereto.

The first electrode 1414 may be divided a first area 1414 a adjacent tothe bank 1418 and a second area 1414 b not adjacent to the bank 1418.The first area 1414 a of the first electrode 1414 has low specificresistance by being performed by hydrogen plasma. In order words, aspecific resistance of the first area 1414 a is lower than that of thesecond area 1414 b in the first electrode 1414. Therefore the quantityof a current flowing through a first area 1414 a adjacent to the bank1418 is larger than that through a second area 1414 b.

In order to perform the hydrogen plasma process, the first electrode isformed, then a photoresist is coated at the second area 1414 b, then thehydrogen plasma is performed on the first area not coated with thephotoresist and then the photoresist is finally peeled, thereby inducingthe same effect as the first electrode with the different thicknesses orseparated with each other.

The organic light emitting device 200 and 1100 according to variousembodiments may solve the problem that because the thickness of theorganic layer formed by a solution process is not flat, the hole is notsmoothly transferred to the thicker area of the organic layer, therebydegrading the light emitting uniformity and changing a recombinationzone forming exitons.

According to various embodiments, one of forming the first electrode inwhich the thicknesses of the area adjacent to a bank is larger than thatof the area not adjacent to the bank, dividing the first electrode intotwo area electrodes which is electrically connected to a plurality oftransistors with the different current disabilities respectively andperforming the area adjacent to the bank in the first electrode byplasma, enables the fist area adjacent to the bank to flow the currentmuch more, thereby preventing degradation of the light emittinguniformity. Therefore it can improve the light emitting efficiency andelongate the lifetime for the organic light emitting device.

In addition, in case the first area of the first electrode is formed ofa multilayer of ITO-IZO, the transmittance in the visible region isimproved and the surface resistance is more lowered so that the effectof improving hole injection can also be obtained.

Although various embodiments have been described up to now withreference to the accompanying drawings, the present invention is notlimited to thereto.

In addition, since terms, such as “including,” “comprising,” and“having” mean that one or more corresponding components may exist unlessthey are specifically described to the contrary, it shall be construedthat one or more other components can be included. All the terms thatare technical, scientific or otherwise agree with the meanings asunderstood by a person skilled in the art unless defined to thecontrary. A term ordinarily used like that defined by a dictionary shallbe construed that it has a meaning equal to that in the context of arelated description, and shall not be construed in an ideal orexcessively formal meaning unless it is clearly defined in the presentspecification.

Although the embodiments of the present invention have been describedfor illustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention. Therefore, theembodiments disclosed in the present invention are intended toillustrate the scope of the technical idea of the present invention, andthe scope of the present invention is not limited by the embodiment. Thescope of the present invention shall be construed on the basis of theaccompanying claims in such a manner that all of the technical ideasincluded within the scope equivalent to the claims belong to the presentinvention.

What is claimed is:
 1. An organic light emitting device, comprising: asubstrate on which a driving transistor is formed; a bank formed on thesubstrate and providing a boundary for a pixel region; a first electrodeformed on the substrate and electrically connected with the drivingtransistor, the first electrode comprising a first and a second crosssectional area both oriented in a direction perpendicular to a verticaldirection of the substrate, the first area adjacent to the bank, thesecond area surrounded by the first area, the first area of the firstelectrode is physically separated from the second area of the firstelectrode by a gap; an organic layer formed on the first electrodewithin the boundary provided by the bank, at least a portion of theorganic layer formed to physically contact the first electrode over thefirst area; and a second electrode formed on the organic layer.
 2. Theorganic light emitting device as claimed in claim 1, wherein the gap isfilled by the organic layer.
 3. The organic light emitting device asclaimed in claim 1, further comprising: a second insulating layer formedin the gap between the first area of the first electrode and the secondarea of the first electrode, the second insulating layer connected toboth the first and second areas of the first electrode.
 4. The organiclight emitting device as claimed in claim 3, wherein the secondinsulting layer comprises at least one from the group consisting ofSiOx, SiNx, SiON, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, PZT,benzocyclobutene, and an acryl based resin.
 5. The organic lightemitting device as claimed in claim 3, wherein the first area of thefirst electrode is in shape of “u” in a direction parallel to thesubstrate and the second area of the first electrode is in shape ofrectangle in the direction parallel to the substrate.
 6. The organiclight emitting device as claimed in claim 3, wherein the drivingtransistor comprises a first driving transistor electrically connectedwith the first area of the first electrode and a second drivingtransistor electrically connected with the second area of the firstelectrode.
 7. The organic light emitting device as claimed in claim 6,wherein a current drivability of the first driving transistor is greaterthan that of the second driving transistor.
 8. The organic lightemitting device as claimed in claim 6, wherein at least one of a channelwidth and a channel length of the first driving transistor is largerthan that of the second driving transistor.
 9. The organic lightemitting device as claimed in claim 6 wherein an electron mobility of anactive layer of the first driving transistor is higher than that of thesecond transistor.
 10. The organic light emitting device as claimed inclaim 1, wherein the second area does not physically contact the bank.11. The organic light emitting device as claimed in claim 1, wherein thepixel region is located within the boundary formed by the bank, andwherein the boundary is located above the first area.
 12. The organiclight emitting device as claimed in claim 1, wherein the bank is formedin a forward tapered shape.
 13. The organic light emitting device asclaimed in claim 1, wherein the organic layer comprises a curvedsurface.
 14. An organic light emitting device, comprising: a substrateon which a driving transistor is formed; a bank formed on the substrateproviding a boundary for a pixel region; a first electrode formed on thesubstrate and electrically connected with the driving transistor, thefirst electrode comprising a first and a second cross sectional areaboth oriented in a direction perpendicular to a vertical direction ofthe substrate, the first area adjacent to the bank, the second areasurrounded by the first area, the first area of the first electrodecomprising a specific resistance that is lower than that of the secondarea of the first electrode; an organic layer formed on the firstelectrode within the boundary provided by the bank, at least a portionof the organic layer formed to physically contact the first electrodeover the first area; and a second electrode formed on the organic layer.15. The organic light emitting device as claimed in claim 14, whereinthe organic layer comprises a concave shape along a surface borderingthe second electrode, the organic layer thinner adjacent to where thesecond area of the first electrode is formed.
 16. The organic lightemitting device as claimed in claim 1, wherein the second area does notphysically contact the bank.
 17. The organic light emitting device asclaimed in claim 1, wherein the pixel region is located within theboundary formed by the bank, and wherein the boundary is located abovethe first area.
 18. The organic light emitting device as claimed inclaim 1, wherein the bank is formed in a forward tapered shape.
 19. Anorganic light emitting device, comprising: a substrate on which adriving transistor is formed; a bank formed on the substrate andproviding a boundary for a pixel region; a first electrode formed on thesubstrate and electrically connected with the driving transistor, thefirst electrode comprising a first and a second cross sectional areaboth oriented in a direction perpendicular to a vertical direction ofthe substrate, the first area adjacent to the bank, and the second areasurrounded by the first area, and the first cross section area beinglarger than the second cross sectional area; a first insulting layerbetween at least a portion of the first electrode and the organic layer,the first insulating layer connected to both the first area and thesecond area of the first electrode; an organic layer formed on the firstelectrode within the boundary provided by the bank; and a secondelectrode formed on the organic layer.
 20. The organic light emittingdevice as claimed in claim 19, wherein the first insulting layercomprises at least one from the group consisting of SiOx, SiNx, SiON,Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, PZT, benzocyclobutene, and an acrylbased resin.